Selection of single-atom for surface charge modulation to promote CO2 activation and stabilize *COOH intermediate for solar fuels

Abstract

Modulating surface charge distribution is a key strategy for enhancing photocatalytic CO2 reduction, as it effectively activates the inert CO2 molecule into a reactive, bent configuration. However, the rational design of such catalysts is fundamentally challenged by the lack of a systematic, predictive guideline for selecting optimal anchored single metal atoms. We address this critical gap by establishing a novel predictive metal selection principle based on the synergistic effect of the single atom's valence electron count and electronegativity. This principle successfully guided the selection of transition metals (Cr, Fe, Ni) anchored onto WO3 nanoplates via wet impregnation, ensuring selective surface modification while preserving bulk properties. The Fe-anchored WO3 catalyst, identified by our principle, demonstrated the most substantial surface electron density localization. This rational optimization led to a remarkable three-fold enhancement in PC-CO2RR efficiency, selectively yielding CO as the primary product. Comprehensive experimental and theoretical analyses confirmed that this localized charge accumulation promotes significantly stronger CO2 chemisorption and critically stabilizes the *COOH key intermediate. Specifically, the reaction became thermodynamically spontaneous with ΔG(*COOH) = -1.73 eV. Our findings establish a strong correlation between localized surface charge density and CO2 activation, providing a fundamental and generalizable guideline for the rational design of high-performance catalytic materials for energy and sustainability applications.